Some of the earliest known furniture has been found at Abydos, Saqqara, and Tarkhan, preserved in the tombs of the kings of the Early Dynastic period and those of their nobles and officials. In the early 1900s, at Tarkhan, W. M. Flinders Petrie discovered a significant collection of early bed frames, which have legs finely carved in bovine form. This indicates the strong influence that royalty had in the lives of the people, for the king was associated with the bull from as early as the first dynasty. The introduction of copper woodworking tools by the late Predynastic period allowed carpenters to carve and cut sophisticated joints in timber elements, which had been impossible to achieve before. Bovine-shaped stool legs of beautiful proportion and striking anatomical detail were also manufactured from hippopotamus ivory. In the second dynasty royal cemetery at Helwan, a number of “ceiling” stelae have been discovered that show the stool as commonly used. It had tall bovine-shaped legs, with a seat strung of plaited rush cord wrapped around the seat rails before being woven across the frame. One important stela at Helwan, of the same period, shows a member of the royal family seated on a chair with a high back, which perhaps represents an early throne.